Because if you rename an item then it loses its properties. This doesn't really matter too much for stone, but a DC of renamed iron blocks is basically useless unless you only plan to use the blocks to build. You can't, for example, convert the blocks back into iron ingots.

So anyone thinking to buy the DC in order to use the iron would end up disappointed.

Should have made it clearer. Renamed blocks can be auctioned in any quantity

That'd be away around the current ruling. This would allow any regular item to be auctioned in any quantity. This change would allow people to auction 27.4 potatoes, or only a single stack of diamonds.

Because if you rename an item then it loses its properties. This doesn't really matter too much for stone, but a DC of renamed iron blocks is basically useless unless you only plan to use the blocks to build. You can't, for example, convert the blocks back into iron ingots.

So anyone thinking to buy the DC in order to use the iron would end up disappointed.

The items don't lose their properties; the name can be removed from any item for the cost of only a few levels.

That'd be away around the current ruling. This would allow any regular item to be auctioned in any quantity. This change would allow people to auction 27.4 potatoes, or only a single stack of diamonds.

The items don't lose their properties; the name can be removed from any item for the cost of only a few levels.

Edit: Also note that the thread you linked here predates 1.8. This thread was in April, and in May EMC upgraded. As mentioned above: I'm positive that's when the behavior changed. Still not fully sure if this is intended or not though, I'll look up those links later on.